U.S. Pat. Nos. 3,941,615; 4,022,951 and 4,209,575 all disclose modular, multicell batteries of particularly unique configurations. In general, such multicell batteries comprise a plurality of frames, each of which is divided into a number of side-by-side active material support areas. The frames are assembled and secured together in a stacked formation so that the perimeter partitions of the frames form the top, bottom and two opposite sides of the battery and the divisions in the frames form cell partitions. Each frame is pasted with active material to form plates with adjacent plates in each frame being of opposite polarity and adjacent plates in each frame being of opposite polarity and adjacent plates in adjoining frames also being of opposite polarity. An electrolyte-porous separator material is provided between adjacent plates in adjoining frames.
U.S. Pat. No. 4,239,839 shows a similar type of battery. However, in the battery illustrated therein, a barrier frame is interposed and secured in the assembly of frames. This barrier or partition frame forms a chemical and electrical barrier between active battery material and frames on opposite sides of the barrier member. By this means, the battery illustrated is effectively divided into two separate batteries. The relative capacity of each such battery can be pre-established, as may be desired for the intended application.
The modular, multicell battery described in the aforementioned patents represents a total departure from traditional, lead-acid battery constructions used for SLI automotive and truck applications and for marine use. Freed from the restrictions of the conventional, premolded container, the capacity of such unique modular batteries can be increased merely by adding more frames and separators.
The advantages of using this type of battery can be substantial. Such modular batteries are susceptible to production in a highly automated manufacturing process and can conceptually involve fewer components than are utilized in conventional lead-acid batteries.
Moreover, from the performance standpoint, such modular batteries can deliver performance equivalent to conventionally made lead-acid batteries with less weight. Indeed, such modular batteries can deliver up to about 30% more current or power output per pound than does a conventional lead-acid battery at 60.degree. F. and higher, due to the shorter current path and due to the lower solid electrical resistance component of the total battery electrical resistance. This accordingly means that, at such elevated temperatures, such modular batteries have lower electrical resistance than a conventionally designed automotive battery of equivalent size. A further advantage of modular batteries of this type is that there should be no intercell connection failure mode in such modular batteries in contrast to conventionally designed automotive batteries in which intercell weld or connection failure in service is one of the principal failure modes.
Modular, multicell batteries of this type are in commercial use, currently being made and sold by the assignee of the present invention. While considered advantageous, the present commercial modular batteries have less than desired characteristics in some respects. First of all, such commercial batteries include many more parts than would be preferred for facile production. Further, several of the parts employed must be assembled with nuts and bolts, or the like. Under some conditions of use, the resulting vibration resistance is less than optimum. Still further, the busbars used have been somewhat susceptible to corrosion. Also, the present commercial design does not allow the optimum flexibility and versatility in manufacture or in performance.
It is accordingly an object of the present invention to provide a modular, multicell battery capable of greater reliability in service. A more specific and related aspect of the present invention provides batteries of this type having substantial resistance to vibration. Yet another specific object is to provide such a modular battery with improved venting means and which allows substantial flexibility in the modes of recharge that can be employed.
Another object of this invention provides a modular, multicell battery which is economical to make and assemble. A more specific and related object lies in the provision of such a battery having a minimum number of components.
A still further object of this invention provides a battery of this type having desirable resistance to corrosion.
Yet another object of the present invention lies in the provision of a modular, multicell battery that readily can be adapted to a specific end use application.
Other objects and advantages will be apparent as the following description proceeds taken in conjunction with the accompanying drawings.